scholarly journals Three-dimensional general relativistic Poynting-Robertson effect. IV. Slowly rotating and nonspherical quadrupolar massive source

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Vittorio De Falco ◽  
Maciek Wielgus
2019 ◽  
Vol 99 (2) ◽  
Author(s):  
Vittorio De Falco ◽  
Pavel Bakala ◽  
Emmanuele Battista ◽  
Debora Lančová ◽  
Maurizio Falanga ◽  
...  

Science ◽  
2012 ◽  
Vol 339 (6115) ◽  
pp. 49-52 ◽  
Author(s):  
Jonathan C. McKinney ◽  
Alexander Tchekhovskoy ◽  
Roger D. Blandford

Accreting black holes (BHs) produce intense radiation and powerful relativistic jets, which are affected by the BH’s spin magnitude and direction. Although thin disks might align with the BH spin axis via the Bardeen-Petterson effect, this does not apply to jet systems with thick disks. We used fully three-dimensional general relativistic magnetohydrodynamical simulations to study accreting BHs with various spin vectors and disk thicknesses and with magnetic flux reaching saturation. Our simulations reveal a “magneto-spin alignment” mechanism that causes magnetized disks and jets to align with the BH spin near BHs and to reorient with the outer disk farther away. This mechanism has implications for the evolution of BH mass and spin, BH feedback on host galaxies, and resolved BH images for the accreting BHs in SgrA* and M87.


2019 ◽  
Vol 623 ◽  
pp. A152 ◽  
Author(s):  
M. Mościbrodzka

Context. Polarimetric observations of black holes allow us to probe structures of magnetic fields and plasmas in strong gravity. Aims. We present a study of the polarimetric properties of a synchrotron spectrum emitted from a relativistic jet using a low-dimensional model. Methods. A novel numerical scheme is used to integrate relativistic polarized radiative transfer equations in a slab geometry where the plasma conditions change along the integration path. Results. We find that the simple model of a non-uniform jet can recover basic observational characteristics of some astrophysical sources with a relativistic jet, such as extremely high rotation measures. Our models incorporate a time-dependent component. A small fluctuation in density or temperature of the plasma along the jet produces significant amounts of fluctuations not only in the fractional linear and circular polarizations, but also in the jet internal rotation measures. Conclusions. The low-dimensional models presented here are developed within the same computational framework as the complex three-dimensional general relativistic magnetohydrodynamics simulations of black hole disks and jets, and they offer guidance when interpreting the results from more complex polarization models. The models presented here are scalable to stationary and transient polarized radio emissions produced by relativistic plasma ejected from around compact objects, in both stellar-mass and supermassive black hole systems.


A fully relativistic formulation of the concept of a perfectly elastic solid is developed with a view to application to such problems as (a) the interaction of gravitational radiation with planetary type bodies such as the Earth, and (b) the vibrations and deformations of neutron star crusts. For applications of the former kind a low-pressure Hookean idealization (i.e. a theory postulating a linear stress-strain relation) will often be sufficient. A prototype version of a relativistic Hookean theory suitable for this purpose has already been given by Rayner (1963), but it will be shown that Rayner’s theory needs minor corrections in order to be strictly self consistent. For applications to neutron stars a purely Hookean theory will in any case be inadequate and to replace it a high-pressure quasi-Hookean idealization is described. This idealization includes the important special case of the perfect (i.e. isotropic) solid in which the elastic properties may be described in term s of just two (nonlinear) functions of state, namely the pressure and the modulus of rigidity. The theory reduces to the familiar perfect fluid idealization in the limit when the modulus of rigidity is zero. The discussion is conceptually based on the use of two distinct manifolds: a fourdimensional manifold of space-time events, with a fundamental pseudo-Riemannian metric, and a three-dimensional manifold X of idealized particles, with a fundam ental measure representing a conserved particle number density. These manifolds are related by a canonical projection which sends world-lines in M onto points in X.


2013 ◽  
Vol 768 (2) ◽  
pp. 115 ◽  
Author(s):  
Christian D. Ott ◽  
Ernazar Abdikamalov ◽  
Philipp Mösta ◽  
Roland Haas ◽  
Steve Drasco ◽  
...  

2017 ◽  
Vol 12 (S331) ◽  
pp. 329-338
Author(s):  
Kei Kotake ◽  
Takami Kuroda ◽  
Kazuhiro Hayama

AbstractIn this contribution, we present results from fully general-relativistic three-dimensional (3D) simulations of a non-rotating 15M⊙ star using different nuclear equations of state (EOSs). We show that the SASI (standing-accretion-shock-instability) activity occurs much more vigorously in models with softer EOS. By performing detailed analysis of the gravitational-wave (GW) emission, we find a new GW signature that is produced predominantly by the SASI-induced downflows to the proto-neutron star. We discuss the detectability of the GW signal by performing a coherent network analysis where multiple detectors including LIGO Hanford, LIGO Livingston, VIRGO, and KAGRA are considered. We point out that the GW signal, whose typical frequency is in the best sensitivity range of the laser-interferometers, could potentially provide the live broadcast that pictures how the supernova shock is dancing in the core. The detection horizon of the signal is estimated as 2~3 kpc for the current generation detectors, which can extend up to ~100 kpc for the third generation detectors like Cosmic Explorer. We furthermore perform a correlation analysis between the SASI-modulated GW and neutrino signals. Our results show that the time correlation of the two signals becomes highest when we take into account the travel timescale of adverting material from the (average) neutrino-sphere to the proto-neutron star surface.


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